Prefabricated concrete element for building a civil engineering structure having an arched wall

ABSTRACT

A civil engineering structure having an arched wall including a plurality of curve shaped elements. Each element bears against one or more other similar elements and has a recess arranged in an outer face for casting a concrete assembly capping piece and reinforcements. Each element also includes at least one rigid bearing piece fastened to the element and has, at a free end of the rigid bearing piece, a surface with a non-planar profile. The rigid bearing piece comes to bear against a similar piece of another element located opposite it. The two rigid bearing pieces have complementary profiles making it possible for them to be wedged vertically.

BACKGROUND OF THE INVENTION

The invention relates to a prefabricated concrete element intended to beassembled with other similar elements in order to form an arched wall ofa civil engineering structure.

It is well known to arrange a passage under an embankment, in particularfor a road traffic lane or for a watercourse, by means of a civilengineering structure comprising the arched wall.

The document entitled "Passages inferieurs voutes" ["ArchedUnderpasses"] of 1978, published by the General Interior TransportDirectorate of the French Ministry of Transport, describes such a civilengineering structure, consisting of a succession of curve shapedelements arranged side by side, forming the arched wall of thestructure, and a raft or two parallel bearing sills supporting the curveshaped elements.

For conduits of small cross-section, the curve shaped elements formingthe arch of the structure may substantially be semi-tubular incross-section. Unfortunately, when the width at the base of thestructure exceeds approximately five meters and the height exceedsapproximately three meters, manufacturing and transporting the elementson site becomes practically impossible. In that case, the arched wall isproduced, on one and the same segment of the structure, by assembling aplurality of the curve shaped elements.

Typically, the curve shaped elements each represent one half of thecross-section of the arched structure. The curve shaped elements bearagainst one another in the region of a keystone and are assembled bymeans of a concrete capping piece cast in situ.

According to a known assembly technique, the curve shaped elements havebearing faces provided with complementary profiled parts capable ofinterlocking and comprise emergent reinforcements projecting from theirexterior.

The curve shaped elements bear directly against one another by beingmutually wedged as a result of the interlocking of the profiled parts.The wedging of the interlocking parts allows for self-positioning of thecurve shaped elements when the elements are assembled, thereby providingthe advantage of reducing or even

The emergent reinforcements of the curve shaped elements aresubsequently connected by means of longitudinal reinforcements and arethen embedded in cast concrete forming the assembly capping piece.

The capping piece is then arranged above the wall of the curve shapedelements. Unfortunately, the position of the capping piece is notconducive to the work of the arched wall when the arched wall undergoesstresses transmitted by the mass of the embankment or by the movement ofthe ground. In fact, in response to the above-described stresses, thecurve-shaped elements deform and tend to pivot relative to one anotherabout an axis located substantially at mid-height of their bearingfaces. The curve shaped elements then transmit very high transversestresses to the capping piece.

This frequently results in the appearance of cracks in the capping pieceor in the curve shaped elements. The cracks considerably impair theresistance of the structure over a period of time.

Moreover, the construction of a longitudinal formwork in the upper partof the structure for the casting of the capping piece is a relativelydifficult and complex operation.

The above-mentioned document of 1978 describes elements which areinterrupted at a distance from the keystone and which comprisereinforcements projecting in the extension of their wall. Scaffoldinghaving a height corresponding to the height of the arch is installed onthe raft in line with the keystone. The scaffolding supports a platehaving a curvature similar to the curvature of the arch. The curveshaped elements are subsequently placed on the raft and shored in such away that the upper edges of each element face one another and come intocontact with the plate. Then, the longitudinal reinforcements areconnected to the reinforcements of the various elements, and theassembly as a whole is embedded in cast concrete. The plate forms aformwork base.

Thus, making it possible to obtain an arch which has a substantiallyhomogenous structure.

However, because of the complexity of installation, the assembly is notused in practice. In fact, the scaffolding would be extremely difficultto mount, position the curve shaped elements by shoring so that theycome into contact with the plate, put in place the reinforcements, whichare of relatively complex design, cast a large quantity of concrete inorder to carry out assembly, and then remove all the scaffolding.

French Patent Application No. 94.09607 describes a structure of theabovementioned type in which each curved element comprises a recessarranged in an outer face for casting the capping piece in a region ofan end intended to be assembled with an end of another element, andreinforcements located in the recess, for assembling with the otherelements. The recess is delimited in the region of a bottom of theelement by projecting fillets.

The recesses of the various elements of the structure form a groovewhich may be filled with concrete in order to form an assembly cappingpiece when the elements are assembled opposite one another.

Although the structure is useful, it does suffer from severaldisadvantages.

In fact, the elements bear against one another only in the region of theends of the fillets and are consequently balanced precariously. In orderto keep the elements in position while the capping piece is being cast,it is necessary to place transverse pieces adjoining the elements. Thetransverse pieces are removed once the capping piece has been cast.

The above-described operations, which are carried out inside thestructure and at the keystone, are relatively long and difficult toaccomplish because the fillets are typically not aligned perfectly.

There is also a great risk that the elements will be dragged off, thusjeopardizing the safety of the personnel working on the site.

The result is that bringing the elements to bear is a difficultoperation involving many precautions.

Furthermore, wedges are to be placed between the ends of the fillets sothat the fillets do not come directly into contact with one another.Failing this, the elements would transmit high transverse stresses tothe capping piece when experiencing deformation. As such, installing thewedges contributes to the structure being more complex to build.

French Patent Application No. 94.09607 further describes elements whichhave ground-bearing feet placed between loop-shaped reinforcements. Thefeet and loops are intended to be embedded in cast concrete to form araft or sills. It is not very easy to engage the longitudinalreinforcements through the loop-shaped reinforcements in view of thepresence of the feet. The adjustment of the position of the elementsrelative to the ground also presents problems in carrying out theengagement step.

French Patent Application No. 93.07578 describes a similar civilengineering structure having elements that bear against on another bymeans of projecting walls. The walls are on an inside of an upper partof the elements. Moreover, the walls delimit a bottom of a recess intowhich the capping piece is to be cast.

The walls are shaped to be connected, with the possibility of theelements being articulated relative to one another, thus entailing therisk that harmful lateral stresses will be exerted on the capping pieceif one or more elements pivot relative to one or more other elementslocated opposite them.

SUMMARY OF THE INVENTION

An object of the invention is to overcome the above-mentioneddisadvantages.

The element in question is intended to bear against one or more otheroppositely located similar elements. The element in question isassembled with the other element or elements by means of a concretecapping piece to form the arched wall of a civil engineering structure.The element in question is similar to the type of element discussed inFrench Patent Application No. 94.09607.

According to the invention, each element comprises at least one rigidbearing piece fastened to the element. Each element also comprises, at afree end, a surface having a non-planar profile. When a first element isbrought to bear against another element located opposite the firstelement, the rigid bearing piece of the first element bears against asimilar rigid bearing piece of the other element. Since the two rigidbearing pieces have complementary profiles, an end of one piece iscapable of engaging the end of the other piece in order to ensure thewedging of the elements.

The elements can thus be wedged perfectly while an assembly cappingpiece is being cast when being brought to bear against one another. Thecapping piece does not require formwork to be built and is arranged inthe extension of the wall of the elements.

Any shoring, installation and removal of the transverse joining piecesand any risk that the elements will be dragged off are therebyeliminated.

The bearing pieces may comprise or receive connecting means, such asbolts, making it possible to ensure that the bearing pieces areconnected to one another, should the casting of the capping piece bepostponed.

Preferably, each bearing piece includes a profile, one part of which isembedded in the wall of the element and another part of which projectsfrom the wall. Each bearing piece also includes a bearing plate fastenedto the free end of this profile, the plate having, depending on whetherthe plate is placed on an element located on one side of the structureor on the element located opposite the latter, either a longitudinalcavity or a longitudinal projection intended to be received in thecavity, in order to allow the two plates to come into engagement.

A board may be fastened to the profile, so as to bear against theelement in order to distribute the forces exerted by the latter on theconcrete element.

Preferably, the element represents one half of the arched cross-sectionof the structure. A series of elements of the structure located on oneside of the structure is offset by approximately one half-width of theelement relative to the series of elements located on the other side ofthe structure. As such, each element comprises at least two bearingpieces located approximately at a quarter and three-quarters of a widthof each element.

Each of the bearing pieces is opposite a bearing piece arranged in thecorresponding part of one of the two elements located opposite oneanother. Thus, the mutual wedging of the various consecutive elements isensured perfectly.

Advantageously, the reinforcements of the element are in the form ofloops, and the bearing pieces, located between two consecutivereinforcements, are inscribed within the loops which the reinforcementsform. The bearing pieces do not constitute an obstacle to the passage ofthe bars or longitudinal reinforcements connecting the reinforcements.

According to a preferred embodiment of the invention, the wall locatedon the inside of the element, in order to delimit the bottom of therecess, consists of a fillet integral with the element. The free endface of the fillet is set back slightly from the bearing interface ofthe bearing pieces.

The fillets of two elements located opposite one another thus cometogether so as to delimit the bottom of the recess receiving theconcrete, which forms the capping piece. Alternatively, a plate may beattached to the mutually opposite elements, after being brought to bearon one another, in order to form the base of the formwork.

According to other features of the invention, the lower edge of eachelement comprises: loop-shaped reinforcements intended to be embedded incast concrete forming a raft or bearing sills; at least two feet comingto bear against the ground, each of the feet including a profile havinga width smaller than that of the reinforcements; and bearing platefastened to the free end of this profile.

The profiles of the feet are no obstacle to the engagement of bars orreinforcements through the loops which the reinforcements form, thusmaking it easier to install the bars or reinforcements.

Advantageously, the feet are provided with adjusting means to adjusttheir length, and hence the height of the element relative to theground. It thus becomes possible for the element to be positioned.

These and other objects of the inventory will be described in or beapparent from the following description of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in conjunction with the followingdrawings in which like reference numerals designate like elements andwherein:

FIG. 1 is a perspective view of a civil engineering structure accordingto the invention including an arched wall, the arched wall having aplurality of prefabricated elements;

FIG. 2 is a partial enlarged perspective view of three of the elementsaccording to the invention during installation;

FIG. 3 is a partial cross-sectioned end view of an upper part of twoelements after assembly, according to the invention; and

FIG. 4 is an englarged elevational view of a base of an elementaccording to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

FIG. 1 shows a civil engineering structure 1 having an arched wall 2.The structure 1 is intended to be covered by an embankment and makes itpossible to arrange a passage under the embankment, such as, forexample, for a road traffic lane or a watercourse.

The structure 1 consists of a succession of curve shaped elements 5arranged side by side to form the arched wall 2, and two parallelbearing sills 6 to support the elements 5.

The elements 5 each represent one half of the arched cross-section ofthe structure 1 and bear against one another in the region of thekeystone.

The series of elements 5 located on one side of the structure 1 areoffset by one half-width of an element 5 relative to elements 5 locatedon the other side of the structure 1. At its ends, the structure 1comprises two half-elements 5a, the width of which is equal to half thatof the elements 5, so that the structure 1 is interrupted by a plane endface.

FIGS. 2 and 3 show upper portions of two elements 5 located opposite oneanother.

Each element 5 has a recess 10 arranged in an outer face, the recess 10being delimited laterally by an end face 11 and by a fillet 12 in aregion of a bottom of the element 5. The fillet 12 is located on theinside of the element 5.

A first set of loop-shaped reinforcements 15 project from the end face11. The reinforcements 15 are arranged in vertical planes, perpendicularto a longitudinal axis of the structure 1, and are offset relative tothe reinforcements 15 of an element 5 located opposite thereto, so as tointersect when the elements 5 are assembled, as shown in FIG. 3.

Each element 5 further includes two rigid bearing pieces 16 fastened tothe element 5 located approximately at a quarter and three-quarters of awidth of the element 5. The pieces 16 project from the end face 11 andare located between two consecutive reinforcements 15. The pieces 16 areinscribed within the loops, which the reinforcements 15 form.

Each bearing piece 16 has a cross-section with an I-shaped profile 17,one part of which is embedded in the end face 11 of the element 5 andanother part of which projects from the end face 11. A bearing plate 18is fastened to a free end of the profile 17 and a board 19 is fastenedto an attached end of the profile 17 embedded in the end face 11.

Each bearing plate 18 has either a longitudinal cavity 21 or alongitudinal projection 22 intended to be received in the cavity 21, sothat two plates 18 can engage each other.

Furthermore, the bearing plates 18 comprise holes 25 capable ofreceiving bolts 26, as shown in FIG. 3.

As can be seen in FIGS. 2 and 3, the fillets 12 have a length such that,in the position in which corresponding elements 5 bear against oneanother, the free end faces 11 of the fillets 12 are set back slightlyfrom the bearing interface of the plates 18.

As can be seen in FIGS. 1 and 4, a lower end face of each element 5includes a second set of loop-shaped reinforcements 30 extendingtherefrom. The reinforcements 30 are ultimately embedded in castconcrete to form the sills 6. The lower end face of each element 5 alsohas at least two feet 31 extending therefrom to bear against the ground.Each of the feet 31 has a profile 32 with an I-shaped cross-section anda bearing plate 33 fastened to the free end of the profile 32.

The reinforcements 30 are also arranged in vertical planes,perpendicular relative to the longitudinal axis of the structure 1.

The feet 31 are located between two consecutive reinforcements 30 andare inscribed within the loops which the various reinforcements 30 form.

The bearing plates 33 have internally threaded holes for receivingscrews 34. The screws 34 may bear against plates 35 placed on the groundor on so-called "blinding" concrete.

In practice, the elements 5 are brought to bear against one another insuch a way that the various bearing plates 18 engage one another.

The screws 34 make it possible, where appropriate, to adjust the spacingbetween the plates 33 and 35, hence the height of each element 5relative to the ground can also be adjusted.

An adhesive sealing tape 40 is placed astride the ends of the fillets12.

Longitudinal reinforcements 41, 42 are engaged through thereinforcements 15 and 30, and formwork is built for the purpose ofcasting the sills 6. Concrete is subsequently poured into the groovewhich the aligned recesses 10 of the various elements 5 form, in orderto constitute a capping piece 43 for assembling the elements 5, and intothe formwork, in order to constitute the sills 6.

The bolts 26 ensure the plates 18 are kept in contact with one another,should the casting of the capping piece 43 be postponed.

The invention thus provides elements 5 having the numerous advantagesmentioned above, in particular that whereby the said elements can bewedged perfectly, when they are brought to bear against one another,while the capping piece 43 is being cast, and that making it possible toobtain a capping piece 43 located in the extension of the wall of theelements 5, without formwork being built.

While the invention has been described in conjunction with specificembodiment thereof, it is evident that many alternatives, modificationsand variations may be apparent to those skilled in the art. Accordingly,the preferred embodiment of the invention as set forth herein isintended to be illustrative, not limiting. Various changes may be madewithout departing from the spirit and scope of the invention.

What is claimed is:
 1. A set of interconnectable prefabricated concreteelements to form an arched wall of a civil engineering structure, eachelement comprising:a free end having an outer face; a recess formed inthe outer face; a first set of reinforcements projecting from the outerface into the recess, the first set of reinforcements interconnectingthe element to a corresponding first set of reinforcements of acorresponding element; at least one rigid bearing piece fastened to theouter face of the free end, each rigid bearing piece projecting from theouter face into the recess and having a free end surface with anon-planar profile; and a capping piece cast in the recess, wherein whenthe element is brought to bear against the corresponding element havingat least one corresponding rigid bearing piece with a free end having aprofile complementary to the non-planar profile of the element, thecorresponding element being located opposite the element, the non-planarprofile of the free end of each rigid bearing piece engages thecomplimentary profile of the free end of the corresponding rigid bearingpiece of the corresponding element to ensure the wedging of the elementand the corresponding element.
 2. The set of elements according to claim1, wherein each rigid bearing piece comprises connecting means forconnecting the element and corresponding element together.
 3. The set ofelements according to claim 1, wherein each rigid bearing piece has abearing plate fastened to the free end having the non-planar profile,the bearing plate having one of either a longitudinal cavity or alongitudinal projection intended to be received in the longitudinalcavity so that the element can engage the corresponding element.
 4. Theset of elements according to claim 3, wherein each rigid bearing piececomprises a board fastened to the element from which each rigid bearingpiece extends.
 5. The set of elements according to claim 1, wherein eachelement represents one half of the arched wall of the civil engineeringstructure, and that a series of elements located on one side of thestructure is offset by approximately one half-width of the elementrelative to a series of corresponding elements located on another sideof the structure, and that the rigid bearing pieces of the elements andcorresponding elements are located along approximately a quarter andthree-quarters of a width of the elements and corresponding elements. 6.The set of elements according to claim 1, wherein the reinforcements ofthe first set of reinforcements are loops, and in that the rigid bearingpieces located between two consecutive reinforcements are inscribedwithin the loops.
 7. The set of elements according to claim 1, wherein abottom of the recess is a fillet integral with the element, a free endface of the fillet is set back from a bearing interface of each of therigid bearing pieces.
 8. The set of elements according to claim 1,wherein a bottom end of each element further comprises:a second set ofreinforcements extending from the bottom end, the second set ofreinforcements capable of being embedded in cast concrete forming one ofeither a raft or bearing sills; and at least two feet extending from thebottom end and being capable of bearing against a ground surface, eachof the feet having a profile with a width smaller than a width of thesecond set of reinforcements and a width of a bearing plate fastened toa free end of the profile.
 9. The set of elements according to claim 8,wherein the feet have adjusting means for adjusting a vertical height ofeach element relative to the ground surface.
 10. The set of elementsaccording to claim 2, wherein the connecting means are bolts.
 11. Theset of elements according to claim 8, wherein each reinforcement of thesecond set of reinforcements is loop-shaped.
 12. The set of elementsaccording to claim 9, wherein the adjusting means are a plate and aplurality of receiving screws that engage a bottom surface of thebearing plate.